1. Field of the Invention
The present invention relates to a chip-type resonator and a method of manufacturing the same, and more particularly, it relates to a chip-type resonator (the term "resonator" includes a vibrator throughout the specification) utilizing vibration of a piezoelectric member and a method of manufacturing the same.
2. Description of the Prior Art
As shown in FIG. 1, a conventional chip-type resonator comprises a piezoelectric member 1, a pair of inner electrodes 2 and 3 embedded in the piezoelectric member 1 and a pair of outer electrodes 4 and 5 provided on side surfaces of the piezoelectric member 1. The pair of inner electrodes 2 and 3 are arranged to be parallel to each other and spaced apart by a distance in the direction of thickness of the member 1. One of the inner electrodes 2 and 3 is connected to the outer electrode 4 and the other one is connected to the outer electrode 5. Further, the piezoelectric member 1 is polarized in the direction shown by an arrow. The chip-type resonator of such structure is disclosed in Japanese Patent Laying-Open Gazette No. 85613/1983 and in a paper titled "Energy Trapping Type Ceramic Vibrator Having Inner Electrodes", 7th Symposium on Ultrasonic Electronics, Dec. 1986, Kyoto, pp. 125-126.
When voltage of a prescribed frequency is applied between the outer electrodes 4 and 5, a portion of the piezoelectric member 1 between the inner electrodes 2 and 3 expands or contracts to cause resonance of the chip-type resonator.
Upon such resonance of the piezoelectric member 1 between the inner electrodes 2 and 3, vibration energy is transmitted toward major surfaces 6 and 7 of the piezoelectric member 1. Therefore, the vibration energy generated between the inner electrodes 2 and 3 is not trapped between the inner electrodes 2 and 3 but leaks to the exterior of the resonator. Thus, when the aforementioned conventional chip-type resonator is directly face-bonded on a substrate, a desired resonance characteristic cannot be obtained because of turbulence in its response.